Morphological abnormalities of the X chromosome are well documented and have been extensively reviewed and discussed by Ferguson-Smith (1965). They include isochromosome of the long arm, deletions of the long and short arms, ring chromosomes, and chromosomal fragments. Other types of abnormality are rare. Engel and Forbes (1965) described a chromatin negative girl (Patient No. 27) with a mosaic...

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Pallister Killian syndrome (OMIM: # 601803) is a rare multisystem disorder typically caused by tissue limited mosaic tetrasomy of chromosome 12p (isochromosome 12p). The clinical manifestations of Pallister Killian syndrome are variable with the most common findings including craniofacial dysmorphia, hypotonia, cognitive impairment, hearing loss, skin pigmentary differences and epilepsy. Isochr...

Loss of heterozygosity (LOH), a causal event in cancer and human genetic diseases, frequently encompasses multiple genetic loci and whole chromosome arms. However, the mechanisms by which such extensive LOH arises, and how it is suppressed in normal cells is poorly understood. We have developed a genetic system to investigate the mechanisms of DNA double-strand break (DSB)-induced extensive LOH...

Tetrasomy 9p is a rare clinical syndrome and about 30% of known cases exhibit chromosome mosaicism. The cases with tetrasomy 9p mosaicism have been reported to show the various phenotypes. On the other hand, Klinefelter syndrome is well recognized chromosomal abnormality caused by an additional X chromosome in males (47,XXY), and the characteristic clinical findings include tall stature, immatu...

To determine which segments of a chromosome arm are responsible for the initiation of chiasmate pairing in meiosis, a series of novel isochromosomes was developed in hexaploid wheat (Triticum aestivum L.). These isochromosomes are deficient for different terminal segments in the two arms. It is proposed to call them "asymmetrical." Meiotic metaphase I pairing of these asymmetrical isochromosome...

PURPOSE Carcinoids are neuroendocrine tumors and most frequently occur within tissues derived from the embryonic gut. These tumors can occur in any organ site but are rare in the testis. The cell type giving rise to testicular carcinoid is unknown. We hypothesized that testicular carcinoid may have a germ cell origin. EXPERIMENTAL DESIGN We describe our analysis of protein and genetic markers...